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f46121bd MJ |
1 | /* |
2 | * kgdb support for ARC | |
3 | * | |
4 | * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | */ | |
10 | ||
11 | #include <linux/kgdb.h> | |
1540c85b | 12 | #include <linux/sched.h> |
68db0cf1 | 13 | #include <linux/sched/task_stack.h> |
f46121bd MJ |
14 | #include <asm/disasm.h> |
15 | #include <asm/cacheflush.h> | |
16 | ||
17 | static void to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs, | |
18 | struct callee_regs *cregs) | |
19 | { | |
20 | int regno; | |
21 | ||
22 | for (regno = 0; regno <= 26; regno++) | |
23 | gdb_regs[_R0 + regno] = get_reg(regno, kernel_regs, cregs); | |
24 | ||
25 | for (regno = 27; regno < GDB_MAX_REGS; regno++) | |
26 | gdb_regs[regno] = 0; | |
27 | ||
28 | gdb_regs[_FP] = kernel_regs->fp; | |
29 | gdb_regs[__SP] = kernel_regs->sp; | |
30 | gdb_regs[_BLINK] = kernel_regs->blink; | |
31 | gdb_regs[_RET] = kernel_regs->ret; | |
32 | gdb_regs[_STATUS32] = kernel_regs->status32; | |
33 | gdb_regs[_LP_COUNT] = kernel_regs->lp_count; | |
34 | gdb_regs[_LP_END] = kernel_regs->lp_end; | |
35 | gdb_regs[_LP_START] = kernel_regs->lp_start; | |
36 | gdb_regs[_BTA] = kernel_regs->bta; | |
37 | gdb_regs[_STOP_PC] = kernel_regs->ret; | |
38 | } | |
39 | ||
40 | static void from_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs, | |
41 | struct callee_regs *cregs) | |
42 | { | |
43 | int regno; | |
44 | ||
45 | for (regno = 0; regno <= 26; regno++) | |
46 | set_reg(regno, gdb_regs[regno + _R0], kernel_regs, cregs); | |
47 | ||
48 | kernel_regs->fp = gdb_regs[_FP]; | |
49 | kernel_regs->sp = gdb_regs[__SP]; | |
50 | kernel_regs->blink = gdb_regs[_BLINK]; | |
51 | kernel_regs->ret = gdb_regs[_RET]; | |
52 | kernel_regs->status32 = gdb_regs[_STATUS32]; | |
53 | kernel_regs->lp_count = gdb_regs[_LP_COUNT]; | |
54 | kernel_regs->lp_end = gdb_regs[_LP_END]; | |
55 | kernel_regs->lp_start = gdb_regs[_LP_START]; | |
56 | kernel_regs->bta = gdb_regs[_BTA]; | |
57 | } | |
58 | ||
59 | ||
60 | void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs) | |
61 | { | |
62 | to_gdb_regs(gdb_regs, kernel_regs, (struct callee_regs *) | |
63 | current->thread.callee_reg); | |
64 | } | |
65 | ||
66 | void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs) | |
67 | { | |
68 | from_gdb_regs(gdb_regs, kernel_regs, (struct callee_regs *) | |
69 | current->thread.callee_reg); | |
70 | } | |
71 | ||
72 | void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, | |
73 | struct task_struct *task) | |
74 | { | |
75 | if (task) | |
76 | to_gdb_regs(gdb_regs, task_pt_regs(task), | |
77 | (struct callee_regs *) task->thread.callee_reg); | |
78 | } | |
79 | ||
80 | struct single_step_data_t { | |
81 | uint16_t opcode[2]; | |
82 | unsigned long address[2]; | |
83 | int is_branch; | |
84 | int armed; | |
85 | } single_step_data; | |
86 | ||
87 | static void undo_single_step(struct pt_regs *regs) | |
88 | { | |
89 | if (single_step_data.armed) { | |
90 | int i; | |
91 | ||
92 | for (i = 0; i < (single_step_data.is_branch ? 2 : 1); i++) { | |
93 | memcpy((void *) single_step_data.address[i], | |
94 | &single_step_data.opcode[i], | |
95 | BREAK_INSTR_SIZE); | |
96 | ||
97 | flush_icache_range(single_step_data.address[i], | |
98 | single_step_data.address[i] + | |
99 | BREAK_INSTR_SIZE); | |
100 | } | |
101 | single_step_data.armed = 0; | |
102 | } | |
103 | } | |
104 | ||
105 | static void place_trap(unsigned long address, void *save) | |
106 | { | |
107 | memcpy(save, (void *) address, BREAK_INSTR_SIZE); | |
108 | memcpy((void *) address, &arch_kgdb_ops.gdb_bpt_instr, | |
109 | BREAK_INSTR_SIZE); | |
110 | flush_icache_range(address, address + BREAK_INSTR_SIZE); | |
111 | } | |
112 | ||
113 | static void do_single_step(struct pt_regs *regs) | |
114 | { | |
115 | single_step_data.is_branch = disasm_next_pc((unsigned long) | |
116 | regs->ret, regs, (struct callee_regs *) | |
117 | current->thread.callee_reg, | |
118 | &single_step_data.address[0], | |
119 | &single_step_data.address[1]); | |
120 | ||
121 | place_trap(single_step_data.address[0], &single_step_data.opcode[0]); | |
122 | ||
123 | if (single_step_data.is_branch) { | |
124 | place_trap(single_step_data.address[1], | |
125 | &single_step_data.opcode[1]); | |
126 | } | |
127 | ||
128 | single_step_data.armed++; | |
129 | } | |
130 | ||
131 | int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, | |
132 | char *remcomInBuffer, char *remcomOutBuffer, | |
133 | struct pt_regs *regs) | |
134 | { | |
135 | unsigned long addr; | |
136 | char *ptr; | |
137 | ||
138 | undo_single_step(regs); | |
139 | ||
140 | switch (remcomInBuffer[0]) { | |
141 | case 's': | |
142 | case 'c': | |
143 | ptr = &remcomInBuffer[1]; | |
144 | if (kgdb_hex2long(&ptr, &addr)) | |
145 | regs->ret = addr; | |
146 | ||
147 | case 'D': | |
148 | case 'k': | |
149 | atomic_set(&kgdb_cpu_doing_single_step, -1); | |
150 | ||
151 | if (remcomInBuffer[0] == 's') { | |
152 | do_single_step(regs); | |
153 | atomic_set(&kgdb_cpu_doing_single_step, | |
154 | smp_processor_id()); | |
155 | } | |
156 | ||
157 | return 0; | |
158 | } | |
159 | return -1; | |
160 | } | |
161 | ||
f46121bd MJ |
162 | int kgdb_arch_init(void) |
163 | { | |
164 | single_step_data.armed = 0; | |
165 | return 0; | |
166 | } | |
167 | ||
38a9ff6d | 168 | void kgdb_trap(struct pt_regs *regs) |
f46121bd MJ |
169 | { |
170 | /* trap_s 3 is used for breakpoints that overwrite existing | |
171 | * instructions, while trap_s 4 is used for compiled breakpoints. | |
172 | * | |
173 | * with trap_s 3 breakpoints the original instruction needs to be | |
174 | * restored and continuation needs to start at the location of the | |
175 | * breakpoint. | |
176 | * | |
177 | * with trap_s 4 (compiled) breakpoints, continuation needs to | |
178 | * start after the breakpoint. | |
179 | */ | |
502a0c77 | 180 | if (regs->ecr_param == 3) |
f46121bd MJ |
181 | instruction_pointer(regs) -= BREAK_INSTR_SIZE; |
182 | ||
183 | kgdb_handle_exception(1, SIGTRAP, 0, regs); | |
184 | } | |
185 | ||
186 | void kgdb_arch_exit(void) | |
187 | { | |
188 | } | |
189 | ||
190 | void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip) | |
191 | { | |
192 | instruction_pointer(regs) = ip; | |
193 | } | |
194 | ||
3d01c1ce CG |
195 | static void kgdb_call_nmi_hook(void *ignored) |
196 | { | |
197 | kgdb_nmicallback(raw_smp_processor_id(), NULL); | |
198 | } | |
199 | ||
200 | void kgdb_roundup_cpus(unsigned long flags) | |
201 | { | |
202 | local_irq_enable(); | |
203 | smp_call_function(kgdb_call_nmi_hook, NULL, 0); | |
204 | local_irq_disable(); | |
205 | } | |
206 | ||
f46121bd MJ |
207 | struct kgdb_arch arch_kgdb_ops = { |
208 | /* breakpoint instruction: TRAP_S 0x3 */ | |
209 | #ifdef CONFIG_CPU_BIG_ENDIAN | |
210 | .gdb_bpt_instr = {0x78, 0x7e}, | |
211 | #else | |
212 | .gdb_bpt_instr = {0x7e, 0x78}, | |
213 | #endif | |
214 | }; |